1. Field of Invention
The present invention is directed toward a light module and, more specifically, to a light module having an aperture with a resilient stop element.
2. Description of Related Art
Light modules known in the related art generally include a light source, a light-collecting element, a primary optics or reflector, an aperture with an actuator and secondary optics, also called projection lens. Based on the design and arrangement of the light source and the primary optics, the light module is equipped to transfer the lighting current of the light source into a first light distribution situated in a focal plane of the projection lens. Based on their design and arrangement the secondary optics is equipped to transfer the first light distribution into a second light distribution situated at the front end of the light module.
The aperture has an optically active edge also called an aperture edge. It is flexibly mounted in the light module. Using an actuator it can be moved into the first light distribution in such a way that its aperture edge restricts the first light distribution. Then the aperture edge is represented in the second light distribution as a cut-off line thus forming low beam distribution. To realize high beam distribution, the aperture is moved out of the first light distribution.
Consequently, the actuator is arranged in such a way that the optically active edge of the aperture can be moved into and out of the first light distribution. Such light modules are used in motor vehicles for the purpose of producing different light distributions at the front end of the motor vehicle. As a result, depending on the position of the optically active edge of the aperture, different second light distributions are generated, whereas not all alternatives of low beam light distribution and high beam light distribution are listed here. Where required it is possible to use intermediate positions of the aperture.
There are numerous possibilities for realizing a movable aperture edge which operate with a swivel, rotating, slide or folding mechanism. In road traffic the switch between the operating conditions of the projection module from low beam light to high beam light has to be performed in a very fast manner, i.e., within fractions of a second. Therefore, by means of actuators, the movable apertures are usually moved out of one, the initial position and are stopped by means of a fixed limit stop in another, the new position. In particular, such a limit stop defines the low beam light position of the aperture. However, the high beam light position does not necessarily require a limit stop because there the aperture does not have to be positioned in such a precise manner. Preferably, the limit stop for positioning a low beam light position is arranged at the primary optics or a structure that is rigidly connected with the primary optics in order to establish a defined position of the aperture in relation to the primary optics.
It is possible that in the interior space of the motor vehicle headlights temperatures of more than 100° C. are reached. In order to guarantee the required temperature stability and in order to guarantee the mechanical resilience required for a use in motor vehicles, the aperture, as well as the positioning limit stop usually consist of metal.
In this case, the impact of the aperture at the positioning limit stop generates an undesirable metallic noise which can be disturbing in the area surrounding the vehicle, as well as in the interior space of the vehicle. This is especially the case when the motor is not running. Moreover, when the primary optics consist of hollow, funnel-shaped reflectors, the hollow, funnel-shaped design compounds the disturbing effect by concentrating the sound waves. Also in view of a growing distribution of low-noise vehicles with electric motors, the importance of low-noise headlights is increasing.
One possibility of avoiding limit stop noises involves the use of a movable aperture mechanism in which the aperture is positioned by means of a stepping motor drive. However, this solution involves complex technology and therefore it is cost-intensive.
Against this background, the present invention is based on the objective of designing and developing a light module of a motor vehicle aperture in such a way that undesirable noises which are generated when the aperture impacts a positioning limit stop during the process of switching positions are reduced or even completely avoided.